Kanro Toshinaga signed himself Gōshū Kanro Toshinaga of Takagi, and one raised to in 1976 carries that full inscription cut below the peg-hole. He worked at Kanro in Takagi, in Ōmi Province, across the close of the period and into the . From old times he has been transmitted as a man of the line of Takagi Sadamune of the province, and the published sources repeat the tradition while declining to take it at face value. Examining his extant signed work, they conclude that 'rather than regarding him as a pupil, it is more appropriate to view him as a swordsmith of the period' (弟子とみるよりは同時代の刀工とみるべきものである). His signed pieces are few, a handful of with one long-signed example, a dated and the rare , so he is a name known through a thin but unusually consistent body of work.
The hand that body shows is read first in the forging and the point. Over an that flows and takes in , with gathered thickly and entering, he tempers a shallow worked low and quiet rather than in clove-flower clusters. Into the run , and , the edge breaking up in , with and drawn through it and gathering toward the upper half. The turns in a small round but breaks into at the very point. It is this pairing, the in the steel and the swept of the turn-back, that the published sources name as his constant marks, and on which they rest the reading that 'he is regarded as a swordsmith of Yamato-related character' (大和系の刀工と見られている).
The is the steady thing across his work. mixed at times with and , the grain standing a little and flowing, thick, frequent, the surface bright and clear where the temper widens. On the wider blades the steel opens into a flowing with passages of large grain, and the is described as bright and clear. Over so active a the temper itself stays comparatively restrained, a low base into which and a pointed tendency are mixed, the interest carried in the working of the edge rather than in height of pattern. One signed , the published commentary notes, shows , and in the upper half and a that 'clearly demonstrate Toshinaga's distinctive characteristics' (俊長の特色をよく示し).
His record divides cleanly in two. The first face is the signed , several of them and so preserving his own work untouched, in or with , on which he occasionally carves with a and goma-bashi. Within this group stand his two Important Cultural Properties, a and a double-edged dated Enbun five, the year 1360. The second face is the , unsigned attributed to him from period and school, wide in body and flowing in the , the low and swept carried at full length. The published sources accept one such with the plain judgment that the traditional attribution can be upheld, while granting on another that no single feature compels the name, so the and the are made to carry the where personality alone will not.
What sets him apart is exactly what the judges name in him rather than in his neighbours. His is not the clean clove-flower of but a -laden, Yamato-flavoured manner, the flowing and the marking his steel and his point against the tighter hand; and the working that ties him to the Sadamune circle of his day keeps him distinct from the plainer provincial smiths around him. The connection to Sadamune is read as one of period and shared taste rather than of master and pupil. One wide , intensely -laden with , and spilling into the , the published sources call 'a work truly brimming with martial spirit' (実に覇気漲る一作であり), and an unsigned they receive as 'a fine example that connects closely to the smith's signed works' (同工の有銘作に繋がる佳品である).
For the collector he is a rare early name with a small and largely held record. Fujishiro grades him Jō . He has no National Treasures; his standing rests instead on two Important Cultural Properties, the and the dated Enbun-five , both heritage preserved outside the market, together with a single and six blades among , and a . Of the holders on record one is preserved at the Kōsetsu Museum of Art and another blade at the Tokyo National Museum, and one piece carries Date family provenance, the remaining whereabouts unrecorded. Only the and tier could ever change hands, and even those come to light rarely, his extant signed works being, as the published commentary repeats, exceedingly few. A signed Kanro Toshinaga, with its flowing and swept , is an uncommon thing for a private collector to encounter, and a documented one a notable addition.